Without creating some deal without any reasoning behind it, I think I would be OK with a simple move of picking up a wing player like McCants and Rasheed coming back.
Rondo/Nate
Ray/McCants/Bradley
Pierce/Daniels
KG/Baby
JO/'Sheed/Perk
We have our great starting lineup, a second-team that can put the ball in the hoop and defend, and SIZE. Who could match up with that size up front and scoring ability from the backcourt?
Of course, for all we know Shaq and CP3 could be on the team by training camp.
CP3 and McCants have about the same chances to be on the Celtics roster by training camp.
Shaq could easily have more than both combined, and Sheed is having nightmares of another Regular Season, he'd only play if he unretired like PJ Brown to play when it matters.
Of course, Danny is the one who knows more about that, and hopefully he's exploring all the ways to improve the roster.